// MIT License

// Copyright (c) 2019 Erin Catto

// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:

// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.

#include "settings.h"
#include "test.h"

/// This test shows how to use a motor joint. A motor joint
/// can be used to animate a dynamic body. With finite motor forces
/// the body can be blocked by collision with other bodies.
class MotorJoint : public Test
{
public:
    MotorJoint()
    {
        b2Body* ground = NULL;
        {
            b2BodyDef bd;
            ground = m_world->CreateBody(&bd);

            b2EdgeShape shape;
            shape.SetTwoSided(b2Vec2(-20.0f, 0.0f), b2Vec2(20.0f, 0.0f));

            b2FixtureDef fd;
            fd.shape = &shape;

            ground->CreateFixture(&fd);
        }

        // Define motorized body
        {
            b2BodyDef bd;
            bd.type = b2_dynamicBody;
            bd.position.Set(0.0f, 8.0f);
            b2Body* body = m_world->CreateBody(&bd);

            b2PolygonShape shape;
            shape.SetAsBox(2.0f, 0.5f);

            b2FixtureDef fd;
            fd.shape    = &shape;
            fd.friction = 0.6f;
            fd.density  = 2.0f;
            body->CreateFixture(&fd);

            b2MotorJointDef mjd;
            mjd.Initialize(ground, body);
            mjd.maxForce  = 1000.0f;
            mjd.maxTorque = 1000.0f;
            m_joint       = (b2MotorJoint*)m_world->CreateJoint(&mjd);
        }

        m_go   = false;
        m_time = 0.0f;
    }

    void Keyboard(int key) override
    {
        switch (key)
        {
        case GLFW_KEY_S:
            m_go = !m_go;
            break;
        }
    }

    void Step(Settings& settings) override
    {
        if (m_go && settings.m_hertz > 0.0f)
        {
            m_time += 1.0f / settings.m_hertz;
        }

        b2Vec2 linearOffset;
        linearOffset.x = 6.0f * sinf(2.0f * m_time);
        linearOffset.y = 8.0f + 4.0f * sinf(1.0f * m_time);

        float angularOffset = 4.0f * m_time;

        m_joint->SetLinearOffset(linearOffset);
        m_joint->SetAngularOffset(angularOffset);

        g_debugDraw.DrawPoint(linearOffset, 4.0f, b2Color(0.9f, 0.9f, 0.9f));

        Test::Step(settings);
        DrawString(5, m_textLine, "Keys: (s) pause");
        m_textLine += 15;
    }

    static Test* Create() { return new MotorJoint; }

    b2MotorJoint* m_joint;
    float m_time;
    bool m_go;
};

static int testIndex = RegisterTest("Joints", "Motor Joint", MotorJoint::Create);
